package main.java.indi.zyj.c150.pointer;

public class _01_MergeTwoLists {
    public ListNode mergeTwoLists(ListNode list1, ListNode list2) {
        ListNode head = new ListNode(-1);
        ListNode p, p1, p2;
        p = head; p1 = list1; p2 = list2;
        while (p1 != null && p2 != null){
            if (p1.val <= p2.val){
                p.next = p1;
                p1 = p1.next;
            }else {
                p.next = p2;
                p2 = p2.next;
            }
            p = p.next;
        }

        if (p1 != null){
            p.next = p1;
        }
        if (p2 != null){
            p.next = p2;
        }
        return head.next;
    }
}
